Surprising that it has happened on a GM bat, typically GM press their bats harder and this kind of damage is rare on a GM. Maybe this was one of the drier clefts. In any case, it doesn't look bad actually. It is a minor case of de-lamination.

I would recommend:

1. PVA glue in a syringe with a slightly thicker needle (1mm maybe). Get the glue in every void. Indulging in a bit of excess glue on top is also OK as you can sand it down once it dries.

2. Once you have ensured that there is enough glue, make sure to pack it real tight with some good quality transparent and stretchy packaging take - transparent because you can see through what is happening and stretchy because you would want it to exert some pressure for the glue to stick it properly.

3. Leave it for a day so that the glue can set in.

4. Once set, remove the packaging tape and sand it enough to leave you with a smooth surface.

5. Oil the bat - the symptom is what you see and you would have fixed it, but the cause may be a drier cleft and preserving every bit of moisture is the order of the day. So, go for oiling the blade.

6. Once the oil has dried in enough, go for extratec. ensure that you have 2 layers of fiber glass edge tape on the repaired section to act as an added security.